The present invention is directed towards a method for manufacturing hoses. More specifically, the present invention is directed towards a method for manufacturing finite length curved hoses.
Rubber hoses of curved shape are required in a variety of applications. One example of an application for a curved hose is in automotive radiators. Typically curved hoses are manufactured by extruding a rubber core layer, applying a reinforcement layer over the core layer, and extruding a cover layer over the reinforcement layer to form an indefinite length hose. The uncured hose length is cut to finite lengths and placed manually on rigid mandrels having the shape of the desired finished hose configuration. The mandrels and the uncured hose assemblies are placed in vulcanization units. The lengths of hose are vulcanized on the mandrels in the desired configuration. The finished hoses are removed from the mandrels.
This conventional method of manufacturing curved hoses is very labor-intensive. The desired final hose configuration often requires three-dimensional routing of the hose length. The hose lengths are manually inserted onto and removed from the rigid mandrels. For complex curved hoses, more than one person is often required to insert and remove the hose lengths on and off of the rigid mandrels. While mandrel lubricants are employed, loading and unloading the hose may cause the interior walls of the hoses to rip or tear.
U.S. Pat. No. 4,242,296 discloses a method for producing curved hoses. This method relies upon the use of deformable mandrels and spacers between the mandrels. This disclosed method does not make use of conventional mandrels currently used in manufacturing hoses and requires the additional expense of the spacers that are destroyed with each pair of curved hose manufactured.
U.S. Pat. No. 4,104,098 discloses a method for producing hose. After the hose assembly is prepared, the hose is partially cured in such a manner so that only the inner surface of the hose core is cured prior to applying a reinforcement means, and the remaining layers of the hose. This disclosed method is more times intensive than the present invention, and due to lack of forming the hose core on a mandrel, only relatively lower pressure hoses can be produced by this method.
The present invention is directed to a method for manufacturing a curved hose. The method is comprised of the steps of forming a hose pre-assembly, partially curing the hose on a linear mandrel, and then completing the curing of the hose pre-assembly on a curved mandrel.
In another aspect of the disclosed method of manufacturing curved hoses, the hose pre-assembly is prepared as an indefinite hose length on a flexible linear mandrel. After partially curing the hose pre-assembly, the hose pre-assembly is cut into fixed lengths. The hose lengths are cured on rigid curved mandrels to form curved hose lengths.